排错一般是在测试发现错误后进行，其中找到错误位置占排错总工作量的______。
A．95%
B．5%
C．50%
D．20%
参考答案：A
A．H2CO3⇌2H++CO32-
B．HClO═H++ClO-
C．NaHCO3⇌Na++HCO3-
D．Ba（OH）2═Ba2++2OH-
—Was it there _______ you were away to answer the phone? —There is no doubt about it.
A．that
B．which
C．while
D．where
